We flew into San Francisco’s main international airport (code SFO). After a long flight with a two hour layover in Chicago, we were too tired to try and work out a cheap way to get to the city, so we just jumped in a taxi. It's a very easy process which involves heading out of the main doors in the arrivals lounge and following the many taxi signs. Our taxi into the Fisherman's Wharf area cost fifty dollars plus tip. It is metered, but anywhere in the downtown San Francisco area will cost you about the same. I think our taxi driver was in a hurry to get back to the airport though because the ride was quite hair raising to say the least! If you want to travel in style and take a limousine, it's actually not that much more expensive at about sixty dollars plus tip and you'll find a stand to hire one of these in the same area as the taxi queue.
Like I said, these are the easiest options, but there are a few cheaper (in some cases much cheaper) choices available if you are willing and able. There are three bus routes operating to and from the airport and with fares varying from $1.50 to $4 there are by far the cheapest option. Two of the three buses operate 24 hours a day, but there is a catch: it is probably the slowest way to get into the city. A happier medium is to get the BART train which operates between 4am and 11pm and costs about $5 per person. It goes from the international terminal, although there is a free airport 'Airtrain' that connects it to all of the other terminals.
The city of San Francisco isn't particularly big and sprawling so I'd recommend walking as much as you can so that you can enjoy the quaint and laid back neighbourhoods between the main attractions. Certainly the traffic around both Union Square and Fisherman's Wharf means that walking is a much easier and less stressful option than driving. The only problem is the steep hills that San Francisco is famous for making walking a challenge at times!
There is a fairly comprehensive public transport system that includes buses, street cars and cable cars. We got a map from the tourist information booth at Pier 39, which was free and very handy. We took the bus up to City Hall and the fare was $1.50 per person (there is a fifty cent discount for concessions), which I actually thought was pretty good value. The street cars are used more by commuters and locals than by tourists, although there are a couple of handy ones that run along the waterfront and up to Union Square. The most famous option for getting around though is the Cable Car that climbs some of the steepest streets in the city between Fisherman's Wharf and Union Square. There is a comparatively hefty charge of $6 to use the cars and they are fairly small so fill up very quickly. We found that the stations nearer to the Wharf were quieter than the other end, where there were long queues.
There are a number of options here too. As is usually the case in cities popular with tourists, there are hundreds of 'hop on hop off' tour routes. You can get details from tourist information or from representatives that scatter the tourist spots. There is also the very popular option of biking the bridge, which basically involves hiring a bicycle and riding across the Golden Gate Bridge. There are various packages to choose from, but the most basic is approximately a two hour round trip that will cost around $16 per person, including equipment hire and route plan. By far the most fun way to see the city though is the option we took which is to hire a Go Car. It's a little yellow car with in built satellite navigation that you drive yourself. Along a choice of set routes the car will give you directions and tell you interesting and fun information about the sights you are seeing. It was unbelievably good fun although a little pricey at around $40 an hour. I'd highly recommend it though if your budget stretches that far!